Suitability of Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration versus Paired Transbronchial Biopsy Specimens for Evaluating Programmed Death Ligand-1 Expression in Stage III and IV Lung Cancer: A Comparative Retrospective Study

Objectives: Cancer cells usually escape tumor-reactive T-cell responses using immune checkpoint proteins, such as programmed death protein-1 (PD-1) and its ligand, programmed death ligand-1 (PD-L1). These proteins can be blocked by immune checkpoint inhibitors (ICIs); the decision on ICI-based first-line treatment for advanced lung cancers depends on the PD-L1 levels in tumor specimens. Determining the PD-L1 expression conventionally requires histological specimens from resected tumors and core biopsy specimens. Non-small cell lung cancer (NSCLC) is usually diagnosed at stage III or IV; therefore, only small biopsy specimens, such as those obtained via endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) are available. However, the suitability of EBUS-TBNA specimens determining the PD-L1 expression levels in advanced lung cancers remains unclear.

Materials and Methods: Here, we investigated the concordance rate of PD-L1 expression between EBUS-TBNA and matched transbronchial biopsy (TBB) specimens. Using the 22C3 anti-PD-L1 antibody (immunohistochemistry), we determined the PD-L1 expression levels in paired specimens obtained from 69 patients (50 with advanced NSCLC and 19 with small cell lung cancer [SCLC]), as well as the efficacy of ICIs in these patients.

Results: The concordance rate of PD-L1 expression between the EBUS-TBNA and TBB specimens was 78.3%. The κ values referent to the PD-L1-positive expression rate between EBUS-TBNA and TBB specimens were 0.707 and 0.676 at cutoff limits of ≥1% and ≥50%, respectively. Among the 19 SCLC patients, 16 (84.2%) exhibited no PD-L1 expression in both EBUS-TBNA and TBB specimens. Notably, the progression-free survival of patients with ≥50% PD-L1 expression in the paired specimens who received ICI treatment was 8.3 months.

Conclusion: Collectively, our results validate the use of EBUS-TBNA specimens for the determination of the PD-L1 expression levels in the context of NSCLC and SCLC.

Phase II study of the combination of S-1 with bevacizumab for patients with previously treated advanced non-squamous non-small-cell lung cancer

BACKGROUND

We assessed the efficacy and safety of bevacizumab and S-1 chemotherapy for patients with previously treated advanced non-squamous non-small-cell lung cancer (NSCLC).

METHODS

This was a prospective single-arm study, including patients with non-squamous NSCLC who had received at least one chemotherapy regimen along with a platinum-based regimen. Bevacizumab 15 mg/kg was intravenously administered every 3 weeks, and S-1 40 mg/m² was orally administered twice daily from day 1 (evening) through day 15 (morning). The treatment continued for 3 weeks/cycle until disease progression or until unacceptable toxicities occurred. During the lead-in part, six patients were evaluated for dose-limiting toxicity (DLT) rate. In phase II, the primary endpoint was objective response rate (ORR). Secondary endpoints were progression-free survival (PFS), overall survival (OS), and safety.

RESULTS

In the lead-in part, we evaluated the safety in the first six patients and observed no DLT. In phase II, a total of 46 patients were enrolled from September 2012 to December 2018. The median follow-up duration was 13.7 months [95% confidence interval (CI) 1.4-72.0]. The ORR was 28.3%. The median PFS and OS were 4.3 (95% CI 2.9-5.9) and 15.0 months (95% CI 9.8-30.3), respectively. The most common adverse events were hypertension (65.2%), diarrhea (47.8%), mucositis oral (45.7%), and proteinuria (43.5%), and the most common grade 3 adverse events were hypertension (23.9%) and proteinuria (6.5%). Grade 4/5 adverse events were not observed.

CONCLUSION

Bevacizumab and S-1 combination chemotherapy showed high activity and were well tolerated in patients with previously treated advanced non-squamous NSCLC.

A Novel System to Detect Circulating Tumor Cells Using Two Different Size-selective Microfilters

BACKGROUND/AIM

Clusters of circulating tumor cells (CTCs) increase metastatic potential compared to single CTC. However, conventional technologies have been unable to generate an accurate analysis of single and cluster CTCs in the peripheral blood. We propose an effective strategy to detect and isolate both single and cluster CTCs using two size-selective microfilters.

MATERIALS AND METHODS

Five ml of whole blood were collected from 10 patients with epidermal growth factor receptor mutation-positive non-small cell lung cancer. Single and cluster CTCs were identified using precision microfiltration membranes with two distinct pore sizes together with anti-EpCAM antibody labeling.

RESULTS

Single and cluster CTCs were detected by simultaneously using two size-selective microfilters. The EGFR-L858R mutation was detected in the DNA from cells captured using both microfilters.

CONCLUSION

Our method can be used to detect and isolate single and cluster CTCs in the whole blood and may facilitate the development of a liquid biopsy strategy.

Susceptibility of patients receiving chemotherapy for haematological malignancies to scabies

BACKGROUND

Scabies is a contagious dermatosis. The risk factors for its transmission remain unclear. A scabies outbreak, involving patients who were receiving chemotherapy for haematological malignancies, occurred at our hospital.

METHODS

The outbreak population was analysed to determine whether the incidence of scabies was higher among contact patients receiving chemotherapy for haematological malignancies.

RESULTS

A patient with crusted scabies was the index case, and 18 of 78 contact healthcare workers (HCWs) and 22 of 135 contact patients were diagnosed with classical scabies. Ten of 17 contact patients with haematological malignancies and 12 of 118 contact patients with other diseases were infected with scabies. The incidence rate was significantly higher among the patients with haematological malignancies (P<0.001). The patients with haematological malignancies had a significantly lower mean minimum neutrophil count than those with other diseases (1159/μL vs 3761/μL, P=0.0012). Most haematological patients did not require special nursing assistance, suggesting that the higher incidence of scabies among these patients resulted from their immunodeficiency rather than greater skin-to-skin contact with infected HCWs.

CONCLUSION

Our study suggests that patients receiving chemotherapy for haematological malignancies are more susceptible to scabies than patients with other diseases, and require stricter protection.

Drug resistance mechanisms in Japanese anaplastic lymphoma kinase-positive non-small cell lung cancer and the clinical responses based on the resistant mechanisms

The treatment for anaplastic lymphoma kinase (ALK)-positive lung cancer has been rapidly evolving since the introduction of several ALK tyrosine kinase inhibitors (ALK-TKI) in clinical practice. However, the acquired resistance to these drugs has become an important issue. In this study, we collected a total of 112 serial biopsy samples from 32 patients with ALK-positive lung cancer during multiple ALK-TKI treatments to reveal the resistance mechanisms to ALK-TKI. Among 32 patients, 24 patients received more than two ALK-TKI. Secondary mutations were observed in 8 of 12 specimens after crizotinib failure (G1202R, G1269A, I1171T, L1196M, C1156Y and F1245V). After alectinib failure, G1202R and I1171N mutations were detected in 7 of 15 specimens. G1202R, F1174V and G1202R, and P-gp overexpression were observed in 3 of 7 samples after ceritinib treatment. L1196M + G1202R, a compound mutation, was detected in 1 specimen after lorlatinib treatment. ALK-TKI treatment duration was longer in the on-target treatment group than that in the off-target group (13.0 vs 1.2 months). In conclusion, resistance to ALK-TKI based on secondary mutation in this study was similar to that in previous reports, except for crizotinib resistance. Understanding the appropriate treatment matching resistance mechanisms contributes to the efficacy of multiple ALK-TKI treatment strategies.

The prevalence and clinical features of asthma-COPD overlap (ACO) definitively diagnosed according to the Japanese Respiratory Society Guidelines for the Management of ACO 2018

Background Asthma-COPD overlap (ACO) is a disease that shares clinical features of both asthma and COPD. The purpose of this study is to investigate the prevalence and clinical features of ACO. Methods We retrospectively reviewed data for 170 patients with persistent airflow limitation and diagnosed them according to "The Japanese Respiratory Society Guidelines for the Management of ACO 2018". Results Of the 170 patients, 111 were diagnosed as follows : COPD (74 patients, 66.6%), ACO (34 patients, 30.6%), and asthma (3 patients, 2.8%). There was no significant difference in clinical features between ACO and COPD patients. The following pulmonary function tests were significantly lower in ACO than in COPD patients : forced expiratory volume in 1 second/forced vital capacity, peak expiratory flow, maximal mid-expiratory flow, and the maximum expiratory flow at 50%and75%. The following respiratory impedance parameters were significantly higher in ACO than in COPD patients : respiratory resistance (Rrs) at 5 Hz (R5), Rrsat 20 Hz (R20), R5-R20, and low-frequency reactance area. Conclusions About 30% of patients with persistent airflow limitation were diagnosed with ACO. ACO patients had lower lung function and higher respiratory impedance compared with COPD patients. J. Med. Invest. 66 : 157-164, February, 2019.

Barcode sequencing identifies resistant mechanisms to epidermal growth factor receptor inhibitors in circulating tumor DNA of lung cancer patients

Most patients with epidermal growth factor receptor (EGFR) mutation‐positive non‐small cell lung cancer (NSCLC) will inevitably develop acquired resistance induced by treatment with EGFR tyrosine kinase inhibitors (EGFR‐TKI). The mechanisms of resistance to EGFR‐TKI are multifactorial, and the detection of these mechanisms is critical for treatment choices in patients who have progressed after EGFR‐TKI therapy. We evaluated the feasibility of a molecular barcode method using next‐generation sequencing to detect multifactorial resistance mechanisms in circulating tumor DNA and compared the results with those obtained using other technologies. Plasma samples were collected from 25 EGFR mutation‐positive NSCLC patients after the development of EGFR‐TKI resistance. Somatic mutation profiles of these samples were assessed using two methods of next‐generation sequencing and droplet digital PCR (ddPCR). The positive rate for EGFR‐sensitizing mutations was 18/25 (72.0%) using ddPCR, 17/25 (68.0%) using amplicon sequencing, and 19/25 (76.0%) using molecular barcode sequencing. Rate of the EGFR T790M resistance mutation among patients with EGFR‐sensitizing mutations was shown to be 7/18 (38.9%) using ddPCR, 6/17 (35.3%) using amplicon sequencing, and 8/19 (42.1%) using molecular barcode sequencing. Copy number gain in the MET gene was detected in three cases using ddPCR. PIK3CA,KRAS and TP53 mutations were detected using amplicon sequencing. Molecular barcode sequencing detected PIK3CA,TP53,KRAS, and MAP2K1 mutations. Results of the three assays were comparable; however, in cell‐free DNA, molecular barcode sequencing detected mutations causing multifactorial resistance more sensitively than did the other assays.

Correlation between serum adenosine deaminase activity and efficacy of anti-programmed cell death-1 antibody

OBJECTIVE

Serum adenosine deaminase (ADA) activity is a marker of immune reaction to several diseases. We evaluated changes in serum ADA in patients with lung cancer undergoing chemotherapy or anti-programmed cell death-1 (PD-1) therapy to examine the correlation between serum ADA and the therapy efficacy.

MATERIALS AND METHODS

We assessed 50 patients with advanced lung cancer receiving chemotherapy or anti-PD-1 therapy. Serum ADA was measured before and on day 7 of the first treatment cycle and day 0 of subsequent cycles. Correlations between ADA change and efficacy of treatment were evaluated.

RESULTS

Of the 50 patients, 20 were treated with chemotherapy and 30 were treated with anti-PD-1 therapy. Serum ADA decreased significantly between baseline and day 7 of the first cycle in patients undergoing chemotherapy, regardless of response (partial response [PR] or stable disease [SD]: -23% [-38 to +32; p =  0.002]; progressive disease [PD]: -12% [-42 to +6; p =  0.500]). Conversely, in patients undergoing anti-PD-1 therapy, serum ADA increased significantly between baseline and 7 days after the first dose and before subsequent doses in patients who had PR or SD. (day 7 of first cycle: +6% [-10 to +34; p =  0.034], day 0 of second cycle: 8% [-5 to +37; p =  0.002], day 0 of third cycle: 9% [-3 to +55; p =  0.002]). However, serum ADA did not significant change in PD patients undergoing anti-PD-1 therapy. Furthermore, early increases in serum ADA were associated with longer progression-free survival in patients receiving anti-PD-1 therapy (p =  0.006).

CONCLUSION

Changes in serum ADA could be used to predict clinical benefit from anti-PD-1 therapy in patients with lung cancer. The association between changes in serum ADA and the efficacy of ant-PD-1 therapy thus remains inconclusive and requires further study.

Correlation between thyroid transcription factor-1 expression, immune-related thyroid dysfunction, and efficacy of anti-programmed cell death protein-1 treatment in non-small cell lung cancer

Background

Recent studies have suggested a correlation between immune-related thyroid dysfunction (irTD) and the superior efficacy of anti-programmed cell death protein-1 (anti-PD-1) treatment in non-small cell lung cancer (NSCLC). Embryologically, the lung and thyroid are similar in origin, and thyroid transcription factor-1 (TTF-1) expresses in both organs, including NSCLC. We explored our hypothesis that TTF-1 expression in NSCLC might correlate with irTD incidence and anti-PD-1 treatment efficacy.

Methods

We identified 132 patients with NSCLC treated with anti-PD-1 antibody at our hospital between December 2015 and June 2017. We evaluated TTF-1 expression in tumor by immunohistochemistry using a mouse monoclonal antibody (clone 8G7G3/1, 1:100, Dako). IrTD was defined as two or more successive abnormal levels of thyroid-stimulating hormone (TSH) during anti-PD-1 treatment. We retrospectively assessed correlations between TTF-1 expression in tumor, irTD incidence, and anti-PD-1 treatment efficacy.

Results

Of 132 patients, 67 (51%) and 65 (49%) were positive and negative for TTF-1, respectively. We observed irTD in 19 patients (6 positives and 13 negatives for TTF-1). The incidence of irTD was 9% and 20% in TTF-1-positive and TTF-1-negative NSCLCs, respectively (P=0.086). Particularly, in non-squamous (NSQ) cell carcinomas, the irTD incidence was significantly higher in patients negative for TTF-1 (30%) than in those positive for TTF-1 (9%; P=0.010), and TTF-1 expression was identified as a significant risk factor for irTD on multivariate logistic regression analysis [odds ratio (OR), 0.18; 95% confidence interval (CI), 0.05-0.59; P=0.005]. Furthermore, longer median progression-free survival (10.3 months) was observed in patients with TTF-1-negative NSCLC with irTD compared to those with TTF-1-positive NSCLC with irTD, TTF-1-positive NSCLC without irTD, and TTF-1-negative NSCLC without irTD (4.2, 1.4, and 2.4 months, respectively).

Conclusions

TTF-1 expression in NSCLC might correlate with irTD and anti-PD-1 treatment efficacy.

Abstract P2-08-37: The prognostic impact of synaptojanin 2 expression in estrogen receptor α-positive breast cancer patients

Background: Synaptojanin 2 (SYNJ2) was reported to be a druggable mediator of metastasis. It is overexpressed and amplified in breast cancer, particularly estrogen receptor α (ERα)-positive breast cancer. SYNJ2 was also shown to promote cell migration and invasion in breast cancer xenograft cultures and lung metastasis in mice. Here, we investigated SYNJ2 mRNA expression in breast cancer patients during long-term follow-up.

Materials and methods: A total of 434 invasive breast cancer tissues were analyzed for SYNJ2mRNA expression using TaqMan PCR, and the correlation of this expression with patient clinicopathological factors was determined. We also examined the expression of markers associated with tumor-initiating capacity, such as SNAI1, SNAI2, and VIM. Survival curves were analyzed using the Kaplan–Meier method. Cox proportional hazards regression analysis was used for univariate and multivariate analyses of prognostic values.

Results: The median follow-up period was 10.7 years. We found positive correlations between high expression of SYNJ2 mRNA and shorter disease-free survival in breast cancer patients (P=0.049), which was limited to ERα-positive patients (P=0.020) and not seen in ERα-negative patients (P=0.863). High SYNJ2 mRNA levels were positively correlated with high tumor grade, ERα negativity, and node positivity. Multivariate analysis indicated that high SYNJ2 mRNA expression was an independent factor for poor disease-free survival in breast cancer patients.

Multivariate analysis of poor disease-free survival   DFS    Mutivariate   All patientsp valueHR (95%CI)Tumor size2cm and fewer1540.43151 (Reference) more than 2cm280 1.19 (0.78-1.85)Lymph node metastasisNegative2190.0001 and fewer1 (Reference) Positive184 5.61 (3.59-9.05) Unknown31 2.40 (0.89-5.48)Grade1,22330.38471 (Reference) 3195 1.20 (0.79-1.81) Unknown6 0.17 (1.78-3.49)ER statusPositive3370.02621 (Reference) Negative97 2.06 (1.87-4.07)PgR statusPositive2930.39511 (Reference) Negative141 1.30 (0.70-2.28)SYNJ2 mRNA expressionlow2170.02251 (Reference) high217 1.57 (1.07-2.34)

Conclusion:High SYNJ2 expression was shown to be an independent predictive factor of poor prognosis in ERα-positive breast cancer patients. SYNJ2 could therefore be used as a candidate biomarker and therapeutic target in breast cancer.

Citation Format: Nishikawa S, Kondo N, Wanifuchi-Endo Y, Hisada T, Uemoto Y, Katagiri Y, Dong Y, Kato H, Takahashi S, Toyama T. The prognostic impact of synaptojanin 2 expression in estrogen receptor α-positive breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-37.

Abstract P3-03-34: Sentinel lymph node biopsy is unnecessary in ductal carcinoma in situ patients diagnosed by biopsy

Background: Japanese Breast Cancer Society Clinical Practice Guidelines for Breast Cancer 2018 state that sentinel lymph node (SN) biopsy is unnecessary for patients treated with breast-conserving therapy (BCT) and with an expected final pathological diagnosis of ductal carcinoma in situ (DCIS). Regardless of whether they were diagnosed with DCIS by biopsy before surgery, 78% of patients currently undergo axial procedures in Japan because invasive lesions may be detected in surgical specimens. This study examined whether SN biopsy can be omitted in DCIS patients diagnosed by biopsy and which factors are associated with invasion.

Methods: Patients who underwent definitive surgery for DCIS diagnosed by preoperative biopsy at our institution from May 2004 to January 2018 were investigated retrospectively. The factors associated with upstaging to invasive cancer from DCIS were examined with Fisher's exact test and the t-test. (Age, Tumor size, Operation (Mastectomy or BCT), Biopsy method (Core Needle Biopsy or Vaccume-Assisted Biopsy), Mammography (ditected or not-detected), Ultrasound (ditected or not-detected, mass or non-mass), Comedo, ER, PgR, HER2)

Results: A total of 311 patients were enrolled in this study, of whom 277 (89.1%) underwent SN; six of these (2.2%) had SN metastasis. All six cases were upstaging to invasive cancer: five (1.8%) had micrometastasis and one had macrometastasis (0.4%). From a surgical viewpoint, SN metastasis were detected in 3/161 (1.9%) cases treated with mastectomy and 3/150 (2.4%) cases treated with BCT. Although all three cases treated with BCT had micrometastasis, one case treated with mastectomy had macrometastasis (the other two cases had micrometatastasis). A total of 80/311 cases (25.7%) upstaged to invasive cancer and the only predictor of invasion was tumor size on images (p=0.0002). We could not determine the effective cut-off for tumor size because the area under the receiver operating characteristic curve was 0.63&lt;0.70.

Tabule 1.Tumor size on images was the only predictor of invasion. Upstaging (N=80)DCIS (N=231)P valueTumor size: mm (95% Confidence Interval)47.5 (41.9-53.2)33.9 (30.5-37.3)0.0002

Conclusion: Tumor size was found to be the only predictor of invasion. Only 2.2% of DCIS patients had SN metastasis despite the fact that 25.7% patients were upstaged to invasive cancer. We conclude that SN biopsy is not necessary for DCIS patients diagnosed by biopsy.

Citation Format: Uemoto Y, Kondo N, Wanifuchi-Endo Y, Hisada T, Nishikawa S, Katagiri Y, Kato H, Takahashi S, Toyama T. Sentinel lymph node biopsy is unnecessary in ductal carcinoma in situ patients diagnosed by biopsy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-34.

Lung Adenocarcinoma with Lynch Syndrome and the Response to Nivolumab

Lynch syndrome is caused by mutations in mismatch repair genes that lead to microsatellite instability (MSI). An increased number of mutation-associated neoantigens have been observed in patients with high-frequency MSI (MSI-H) cancer; in addition, membranous programmed death ligand-1 (PD-L1) tends to be expressed at higher levels in MSI-H cancers than in microsatellite-stable cancers. MSI-H cancer patients are therefore considered to be susceptible to immune checkpoint blockade. We herein report for the first time a case of lung adenocarcinoma with Lynch syndrome and the response to nivolumab.

Metal-ion-induced expression of gene fragments from subseafloor micro-organisms in the Kumano forearc basin, Nankai Trough

AIMS

Using substrate-induced gene-expression (SIGEX) screening on subseafloor sediment samples from the Nankai Trough, Japan, we identified gene fragments showing an induction response to metal ions.

METHODS AND RESULTS

Environmental DNA libraries in Escherichia coli host cells were tested by the addition of metal ions (Ni²⁺ , Co²⁺ , Ga³⁺ or Mo⁶⁺ ), followed by cell sorting of clones exhibiting green fluorescence upon co-expression of green fluorescence protein downstream of the inserted gene fragments. One clone displayed Ni²⁺ -specific induction, three clones displayed Ga³⁺ -specific induction and three clones displayed an induction response to multiple metal ions. DNA sequence analysis showed that a variety of genes showed induction responses in the screened clones.

CONCLUSIONS

Using the SIGEX approach, we retrieved gene fragments with no previously identified response to metal ions that exhibited metal-ion-induced expression. This method has the potential to promote exploration of gene function through gene-induction response.

SIGNIFICANCE AND IMPACT OF THE STUDY

We successfully linked gene-induction response with sequence information for gene fragments of previously unknown function. The SIGEX-based approach exhibited the potential to identify genetic function in unknown gene pools from the deep subseafloor biosphere, as well as novel genetic components for future biotechnological applications.

Characterization of Computed Tomography Imaging of Rearranged During Transfection-rearranged Lung Cancer

BACKGROUND

Rearranged during transfection (RET)-rearranged non-small-cell lung cancer (NSCLC) is relatively rare and the clinical and computed tomography (CT) image characteristics of patients with an advanced disease stage have not been well documented.

PATIENTS AND METHODS

We identified patients with advanced-stage RET-rearranged NSCLC treated in the Cancer Institute Hospital, Japanese Foundation for Cancer Research, and analyzed the clinical and CT imaging characteristics.

RESULTS

In 21 patients with advanced RET-rearranged NSCLC, RET rearrangements were identified using fluorescence in situ hybridization and/or reverse transcriptase-polymerase chain reaction. The fusion partner genes were identified as KIF5B (57%), CCDC6 (19%), and unknown (24%). CT imaging showed that 12 primary lesions (92%) were peripherally located and all were solid tumors without ground-glass, air bronchograms, or cavitation. The median size of the primary lesions was 30 mm (range, 12-63 mm). Of the 18 patients with CT images before initial chemotherapy, 12 (67%) showed an absence of lymphadenopathy. Distant metastasis included 13 with pleural dissemination (72%), 10 with lung metastasis (56%), 8 with bone metastasis (44%), and 2 with brain metastasis (11%).

CONCLUSION

Advanced RET-rearranged NSCLC manifested as a relatively small and peripherally located solid primary lesion with or without small solitary lymphadenopathy. Pleural dissemination was frequently observed.

Dramatic response to alectinib in inflammatory myofibroblastic tumor with anaplastic lymphoma kinase fusion gene

Inflammatory myofibroblastic tumor (IMT) is a neoplasm characterized by the proliferaton of myofibroblasts with the infiltration of inflammatory cells. There is no standard treatment for patients with recurrent or metastatic IMT. We describe here a patient with hyper-progressive IMT with an anaplastic lymphoma kinase (ALK) fusion gene that dramatically responded to alectinib without adverse events. His dramatic and enduring response supports the observation that alectinib may be considered a good treatment option for rare aggressive ALK-positive tumors.

EGFR T790M mutation after chemotherapy for small cell lung cancer transformation of EGFR-positive non-small cell lung cancer

In non-small cell lung cancer (NSCLC) with an epidermal growth factor receptor (EGFR) mutation, 50%–65% of cases acquire resistance after treatment with EGFR-tyrosine kinase inhibitors (EGFR-TKIs) because of an EGFR T790M point mutation and 3%–14% of these cases transformed to small cell lung cancer (SCLC). Generally, the EGFR T790M secondary mutation develops with ongoing ATP competitive inhibition. We present a case of a 76-year-old woman with lung adenocarcinoma harboring an EGFR-L858R mutation who received first-line gefitinib and developed SCLC transformation. She was administered several chemotherapy agents, including a platinum doublet. The primary lesion that showed SCLC transformation had reconverted to adenocarcinoma with EGFR L858R and T790M mutations at the time of a second re-biopsy. Therefore, she was administered osimertinib, which resulted in clinical remission. This case suggested that serial biopsies are necessary even after SCLC transformation.

Selective gene amplification to detect the T790M mutation in plasma from patients with advanced non-small cell lung cancer (NSCLC) who have developed epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) resistance

Background

The epidermal growth factor receptor (EGFR) T790M mutation is associated with resistance to EGFR tyrosine kinase inhibitors (EGFR-TKIs) in non-small cell lung cancer (NSCLC). However, tissues for the genotyping of the EGFR T790M mutation can be difficult to obtain in a clinical setting. The aims of this study were to evaluate a blood-based, non-invasive approach to detecting the EGFR T790M mutation in advanced NSCLC patients using the PointMan™ EGFR DNA enrichment kit, which is a novel method for the selective amplification of specific genotype sequences.

Methods

Blood samples were collected from NSCLC patients who had activating EGFR mutations and who were resistant to EGFR-TKI treatment. Using cell-free DNA (cfDNA) from plasma, EGFR T790M mutations were amplified using the PointMan™ enrichment kit, and all the reaction products were confirmed using direct sequencing. The concentrations of plasma DNA were then determined using quantitative real-time PCR.

Results

Nineteen patients were enrolled, and 12 patients (63.2%) were found to contain EGFR T790M mutations in their cfDNA, as detected by the kit. T790M mutations were detected in tumor tissues in 12 cases, and 11 of these cases (91.7%) also exhibited the T790M mutation in cfDNA samples. The concentrations of cfDNA were similar between patients with the T790M mutation and those without the mutation.

Conclusions

The PointMan™ kit provides a useful method for determining the EGFR T790M mutation status in cfDNA.

Abstract P3-08-11: The prognostic impact of retinoic acid-induced 2 (RAI2) expression in ERα-positive breast cancer patients

Background: Breast cancer cells disseminate to the bone marrow and form bone metastases in a large majority of late-stage patients. Retinoic Acid-Induced 2 (RAI2) was reported as a putative suppressor of early hematogenous dissemination of tumor cells to the bone marrow in breast cancer, particularly in estrogen receptor α (ERα)-positive breast cancer. Here, we investigated mRNA expression of RAI-2 in breast cancer patients during long-term follow-up.

Materials and methods: A total of 451 invasive breast cancer tissues was available for analysis of RAI2 mRNA using a TaqMan PCR system. We also sought correlations between clinicopathological factors and levels of RAI2 expression in these samples. The expression of markers associated with tumor-initiating capacity, such as SNAI1, SNAI2 and VIM was also analyzed. The median follow-up period was 9.0 years. Survival curves were analyzed using the Kaplan-Meier method. Cox proportional hazards regression analysis was used for univariate and multivariate analyses of prognostic values.

Results: We found positive correlations between low expression of RAI2 mRNA and shorter disease-free survival and overall survival in breast cancer patients (P=0.003, P&lt;0.0001, respectively), which was limited to ERα-positive patients (P=0.04, P=0.0009, respectively), and not seen in ERα-negative patients (P=0.52, P=0.27, respectively). Low RAI2 mRNA levels were positively correlated with high grade, ERα-negativity and PgR negativity. Multivariate analysis indicated that low level RAI2 mRNA expression was an independent factor for survival both overall in breast cancer and in ERα-positive breast cancer patients

Multivariate analysis (ERα-positive breast cancer patients)  OS  Multivariate patientsp valueHR(95%CI)Tumor size≤2cm1390.83691 (Reference) &gt;2cm207 1.08(0.54-2.28)Node statusNegative176&lt;0.00011 (Reference) Positive144 4.72(2.33-10.34)Grade11240.95921 (Reference) 2•3218 0.98(0.50-2.14)RAI2 mRNA expressionhigh140&lt;0.00011 (Reference) middle•low206 4.79(2.14-12.78)

.

Conclusion:We show that low expression of RAI2 is an independent factor predictive of a poor prognosis in ERα-positive breast cancer patients. RAI2 could be a promising candidate biomarker and therapeutic target in ERα-positive breast cancer to prevent dissemination to the bone marrow.

Citation Format: Nishikawa S, Kondo N, Endo Y, Hato Y, Hisada T, Nishimoto M, Dong Y, Okuda K, Kato H, Takahashi S, Nakanishi R, Toyama T. The prognostic impact of retinoic acid-induced 2 (RAI2) expression in ERα-positive breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-08-11.

High ratio of T790M to EGFR activating mutations correlate with the osimertinib response in non-small-cell lung cancer

OBJECTIVES

Osimertinib is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that can overcome resistance due to the Thr790Met (T790M) mutation. However, osimertinib occasionally shows limited efficacy in a small population of patients. We investigated the correlation between the ratio of T790M to EGFR activating mutation and the response to osimertinib.

MATERIALS AND METHODS

Between April 2016 and April 2017, 44 patients started osimertinib therapy at the Cancer Institute Hospital of the Japanese Foundation for Cancer Research. We performed EGFR mutation analysis of cytological samples from 33 patients using droplet digital PCR. We calculated the ratio of T790M to EGFR activating mutations and correlated it with the systemic response to osimertinib.

RESULTS

In tumors from the 33 patients, the average ratio of T790M to EGFR activating mutations was 0.420. Twenty-one of the 33 patients had tumors with a T790M ratio of ≥0.4. The osimertinib response rate was significantly higher (92.3%) in patients with a T790M ratio of ≥0.4 than in those with a T790M ratio of <0.4 (52.6%; p = 0.0237). We examined the correlation between the T790M ratio and the tumor reduction rate and obtained a coefficient of r = 0.417 (p = 0.0175). In patients with a T790M ratio of ≥0.4, the median progression-free survival was 355 days, which was longer, but not significant, than that in patients with a T790M ratio of <0.4 (median: 264 days). In patients with a T790M ratio of ≥0.4, the median treatment duration from first-line therapy onward was 931 days, which was significantly longer than that in patients with a T790M ratio of <0.4 (median, 567.5 days) (p = 0.044).

CONCLUSION

The T790M ratio to EGFR activating mutation in tumor may correlate with the response to osimertinib, and patients with a higher T790M ratio have a longer treatment history.

Adrenal Insufficiency Related to Anti-Programmed Death-1 Therapy

BACKGROUND/AIM

Adrenal insufficiency is one of the adverse events (AEs) associated with anti-programmed death-1 (PD1) therapy. Delaying diagnoses can lead to serious conditions. It is necessary to elucidate detailed clinical features of these AEs.

PATIENTS AND METHODS

Patients treated with anti-PD-1 monotherapy or in combination with anti-cytotoxic T cell lymphocyte-4 therapy at our hospital from January 2013 to December 2016 were identified. The patients' clinical characteristics and laboratory and radiologic findings were collected.

RESULTS

Adrenal insufficiency occurred in 3% of the patients. All patients were male. At the onset of symptoms, eosinophilia (>500/μl) was observed in four cases. Eosinophilia was observed more than a month before onset of symptoms in three cases. Other pituitary hormones remained relatively stable. Radiological evidence of pituitary inflammation was detected only in one case.

CONCLUSION

Most anti-PD1-related adrenal insufficiency cases involved an isolated ACTH deficiency. Eosinophilia may be an early indicator before the onset of symptoms.

The measurement of cough response to bronchoconstriction induced by methacholine inhalation in healthy subjects: An examination using the Astograph method

BACKGROUND

We demonstrated that heightened cough response to bronchoconstriction is a fundamental feature of cough variant asthma (CVA). To evaluate this physiological feature of CVA in daily clinical practice, it is necessary to clarify the cough response to bronchoconstriction in healthy subjects. We evaluated cough response to methacholine (MCh)-induced bronchoconstriction in healthy subjects. A forced oscillometry technique was used to measure airway resistance changes with Mch.

METHODS

Healthy never-smokers (21 men, 20 women; mean 22.3 ± 3.7 years) participated. None had a >3-week cough history, clinically significant respiratory or cardiovascular disorders, or disorders that might put subjects at risk or influence the study results or the subjects' ability to participate. Twofold increasing concentrations of Mch chloride diluted in phosphate-buffered saline (0.039 to 160 mg/mL) were inhaled from nebulizers at 1-minute intervals during subjects' tidal breathing after the baseline respiratory resistance (Rrs) was recorded. Mch inhalation continued until Rrs reached twice the baseline value and forced expiratory volume in 1 second (FEV₁) decreased to <90% of baseline value. Spirometry was measured before Mch inhalation and immediately after Rrs had increased twofold. Coughs were counted during and for 30 minutes after Mch inhalation. The cough reflex sensitivity to capsaicin was also examined.

RESULTS

The number of coughs was 11.1 ± 14.3 (median, 7.0; range, 0 to 71; reference range, 0 to 39.7). There was no significant difference in the cough response between the sexes. The reproducibility of the cough response to bronchoconstriction was sufficient. No correlation existed between the bronchoconstriction-induced cough response and capsaicin cough-reflex sensitivity.

CONCLUSIONS

Using the Astograph method, cough response to bronchoconstriction could be measured easily, safely and highly reproducibly in healthy subjects.

Detection of EGFR mutations in NSCLC patients in clinical practice: Comparison between cobas and Scorpion ARMS method

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Background: Epidermal growth factor receptor (EGFR) mutation is the most important factor for determining the treatment strategy for non-small-cell lung cancers (NSCLCs). Currently, two methods (cobas and Scorpion ARMS) have been approved as companion diagnostics for using EGFR tyrosine kinase inhibitor (TKI). Although there are some differences in the spectrums and sensitivities for detecting EGFRmutations such as exon 19 deletions (ex19del), L858R and T790M mutations, the extent of the differences affecting clinical practice is unclear. Methods: All patients with NSCLC who underwent EGFR mutation tests and treated at our hospital from February 2014 to February 2016 were enrolled. To detect EGFR mutations, the Scorpion ARMS (S) method was used from 2014 to 2015 and thecobasEGFR Mutation Test (C) from 2015 to 2016. We retrospectively investigated the detection rate of each EGFRmutation type and compared the rates between the two methods. Results: A total of 1,287 patients were enrolled. To detect EGFR mutations, 627 patients were tested by the S method and 660 by the C method, respectively. Of 1287 patients, 910 patients underwent initial biopsy, whereas 121 patients underwent re-biopsy after EGFR-TKI failure. EGFRmutations were detected in 130 of 418 (31.1%) patients and 153 of 492 (31.1%) patients by the S and C methods, respectively in the initial biopsy (P = 0.982). However, the detection rate of ex19del was slightly lower in the S method (12.6%) than in the C method (16.3%) (P = 0.105). Conversely, the detection rate of L858R was lower in the C method (13.8%) than in the S method (16.7%), but the difference was not significant (P = 0.252). De novo T790M was detected in one (0.2%) patient by the S method and in none by the C method. In re-biopsy after EGFR-TKI failure, the detection rates of T790M were as follows: 19 of 55 patients (34.5%) by the S method and 20 of 66 (30.3%) by the C method (P = 0.619). Conclusions: The different spectrums and sensitivities of EGFR mutations between the S and C methods were observed; however, they did not significantly affect clinical practice.

Monitoring of peripheral lymphocyte and neutrophil counts to predict efficacy of nivolumab (nivo)

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Background: Programmed death-1 (PD-1) antibody is a key drug for treating non-small cell lung cancer (NSCLC), but the response rate is about 20% in non-selected populations and efficacy is difficult to predict. We examined correlations between peripheral blood tests, including counts of lymphocytes (Lym), neutrophils (Neu), and C-reactive protein (CRP), and the efficacy of nivolumab (nivo) monotherapy. Methods: Eighty NSCLC patients treated with nivo (3mg/kg every 2 weeks) in our hospital between December 2015 and September 2016 were evaluated. Peripheral blood tests on day (d) 0 (the day before 1st nivo), d15 (the day of 2nd nivo), d29 (the day of 3rdnivo) were evaluated. Absolute counts and the change ratio (%) of Lym, Neu and CRP from baseline (d0) were calculated. Response to nivo was evaluated according to RECIST v1.1. Results: Response to nivo was partial response in 23 cases, stable disease in 13 and progressive disease (PD) in 44 patients (overall response rate, 28%; disease control rate, 45%). Absolute counts of Lym, Neu and CRP at baseline did not differ significantly between non-PD and PD (Lym, 1323/µl vs. 1376/µl; Neu, 4830/µl vs. 5189/µl; CRP, 3.48 mg/dl vs. 3.38 mg/dl). Neu was significantly increased from baseline to d15 and d29 in the PD population compared with the non-PD population (δNeu (d15): 25.2% vs. -6.3%, P= 0.008; δNeu (d29): 16.7% vs. -8.6%, P= 0.006). CRP was also significantly increased from baseline to d29 in the PD population compared with the non-PD population (δCRP: 60.1% vs. -21.2%, P= 0.010). In contrast, Lym was significantly increased from baseline to d29 in the non-PD population compared with the PD population (δLym: 9.6% vs. –6.7%, P= 0.010). Conclusions: Changes in peripheral blood test results after nivo differed between non-PD and PD populations. Monitoring of Neu and Lym and CRP may allow prediction of the efficacy of nivo.

Clinical and radiological features of advanced RET-rearranged lung cancer

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Background: RET fusion gene was found in 1–2% of non-small cell lung cancer (NSCLC). Most of the reports published so far investigated only surgical specimens, and details of advanced tumors were unknown. This study explored the clinical and radiological characteristics of RET-rearranged lung cancers in advanced stages. Methods: Among 1,074 advanced NSCLC patients who were treated at The Cancer Institute Hospital, Tokyo, from 2012 to 2016, 14 cases (14/1,074 = 1.3%) were treated as RET- rearranged lung cancer. The cases were identified by FISH and / or by RT-PCR (FISH 3, RT-PCR 2, FISH and RT-PCR 8, unknown 1). The fusion partner genes included KIF5B (n = 10), CCDC6 (n = 1). Three were unknown. The tumor size, location, and shape/margins of the primary tumor as well as lymphadenopathy and site of metastasis were recorded based on computed tomography (CT) images taken right before the initial chemotherapy. Results: The median age of the 14 patients was 64 years (range, 34–79), with 10 patients (71%) over 60 years old. Nine patients (64%) were women, whereas 10 patients (71%) were never smokers. Eight patients were classified as stage IV and 6 underwent recurrence after surgery. We successfully evaluated CT images at the initial chemotherapy of 12 patients. Of the 7 patients whose primary lesions were detectable, all were located peripherally and were of a solid tumor type without ground-glass, air bronchograms, or cavitation. The median size of the primary lesion was 3.0 cm (range, 1.2–6.8), and 3 lesions were less than 3.0 cm. Only 5 patients had lymphadenopathy (4 were of Stage IV, 1 was a recurrence), most of which were isolated with a median size of 1.5 cm (range, 1.2–3.5). The sites of distant metastases included 8 pleural disseminations, 5 lungs, 5 bones, 3 livers, 2 brains, and 0 adrenals. Conclusions: Advanced RET-rearranged lung cancer manifested as a relatively small and peripherally located solid primary lesion with isolated lymphadenopathy. Pleural dissemination was frequently observed, whereas brain metastasis was less frequent. These features differ from EGFR-mutated or ALK-fused lung cancers.

The efficacy and toxicity of osimertinib in T790M-positive NSCLC with acquired resistance to EGFR-TKI in clinical practice

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Background: A Phase III study (AURA3) demonstrated that osimertinib prolonged PFS compared to platinum doublet in patients with T790M-positive non-small-cell lung cancer (NSCLC) exhibiting acquired resistance to epidermal growth factor receptor- tyrosine kinase inhibitor (EGFR-TKI). Although the patients in the study had good PS and only one prior EGFR-TKI treatment, most practical patients had multiple prior EGFR-TKI and poor PS. Moreover, several patients exhibited symptomatic central nervous system (CNS) metastasis in clinical practice. In this study, we evaluated the efficacy and toxicity of osimertinib in clinical practice. Methods: We retrospectively analyzed 30 patients who were treated with osimertinib at our hospital from April 11th 2016 to September 30th 2016. The efficacy and toxicity was compared between the patients with matched and unmatched AURA3 eligibility criteria. Efficacy was evaluated according to RECIST ver.1.1 and toxicity was evaluated using CTCAE ver.4.0. Results: A total of 9 out of 30 patients matched the AURA3 eligibility criteria (PS ≤ 1 and one prior EGFT-TKI) and 21 patients were unmatched (PS ≥ 2 or two or more EGFR-TKI or symptomatic CNS metastasis). The overall response rate(ORR) of osimertinib was 78% and 67% for the matched and unmatched patients, respectively. The disease control rate (DCR) was 100% and 90% for the matched and unmatched patients, respectively. In addition, the response rate of symptomatic CNS metastasis was 67%. Regarding toxicity, grade 3/4 toxicities were observed in 22% of the matched patients and 33% of the unmatched patients. In the matched patients, the most frequent AE was a rash (89%) and the frequent grade 3/4 toxicities were a rash (22%) and pneumonitis (11%). In unmatched patients, the most frequent AE was also a rash (57%), but the frequent grade 3/4 toxicities were pneumonitis (14%), rash (10%), and neutropenia (10%). Conclusions: Both the ORR and DCR in the unmatched patients were slightly lower than the matched patients; however, osimertinib was still found to be beneficial in clinical practice.

Preexistence of CT findings with usual interstitial pneumonia (UIP) pattern correlates to radiation pneumonitis (RP) in non-small cell lung cancer (NSCLC) patients receiving chemoradiotherapy (CRT)

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Background: RP is a major toxicity commonly observed in NSCLC patients who receive CRT; RP prediction is a critical issue. Although preexisting interstitial pneumonia (IP) is considered as one of the risk factors of RP, the correlation between interstitial lung shadows (ILSs) in the pretreatment CT scan and RP is not well examined. Methods: We reviewed patients with stage III NSCLC who received CRT at our hospital from January 2011 until December 2014. The pretreatment CT scans were retrospectively evaluated, and preexisting ILSs were classified according to the ATS/ERS/JRS/ALAT statement for idiopathic pulmonary fibrosis (IPF) as follows: UIP pattern, possible UIP pattern, and others (not UIP pattern). The incidence, severity, and features of RP were compared between ILS patterns. Results: In total, 105 patients with stage III NSCLC had received CRT. ILSs in pretreatment CT scans were identified in 16 (15.2%) of 105 patients. Of all the identified patterns, one (0.9%) was UIP pattern, six (5.7%) were possible UIP pattern, and nine (8.6%) were not UIP pattern. Grade 3 or higher RP was observed in 2 of 7 (28.6%) patients with UIP pattern or possible UIP pattern and 1 of 9 (11.1%) patients with not UIP pattern ( P = 0.55). RP that extended outside the irradiation field like an acute exacerbation of IP was observed in 4 of 7 (57.1%) patients with UIP pattern or possible UIP pattern and 1 of 9 (11.1%) patients with not UIP pattern ( P = 0.106). Conclusions: Preexistence of ILSs classified as UIP pattern or possible UIP pattern should be considered as a risk factor for severe or extensive RP after CRT.

The reasons why re-biopsies were not performed after failure with EGFR-TKI

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Background: Repeat biopsy becomes important to determine subsequent treatment after failure of EGFR-TKI. However, some patients did not receive re-biopsy in real world. Here we retrospectively analyzed the reasons why the patients did not receive re-biopsy. Methods: We reviewed medical records of 235 patients treated with EGFR-TKI at our institution between January 2014 and September 2016 and analyzed the treatment, the progression site after failure of EGFR-TKI and the reasons why they did not receive re-biopsy. Results: 127 of 235 (54%) patients had tumor progression after treatment with EGFR-TKI and 93 (73.2%) of 127 patients received re-biopsy and 34 (26.8%) patients didn’t. The characteristics of 34 patients who did not received re-biopsy were; the median age, 67 years (29-83), male/ female: 12/22, PS0-1/2 ≥:27/7, stage IV/recurrence/other:20/10/4, smoking history never/ex/current: 15/17/2, histology : adeno/other 34/0, EGFR mutation type; 19del/L858R/Other = 13/15/6, prior EGFR-TKI; Gefitinib/Erlotinib/Afatinib/other: 22/9/2/1. The commonest reason why they did not receive re-biopsy was no target lesion to get biopsy (n = 13,38%). CT scans of these patients were retrospectively evaluated and it was confirmed that there were no lesions that could be accessed safely at that time. Central nervous system lesions, multiple small pulmonary lesions and bone metastasis were unaccessible lesions. Although 21 patients had accessible lesions including lung, superficial lymph nodes, pleural effusion, liver, they did not receive re-biopsy because of patient refusal (n = 9), worsening of general condition (n = 3), need for other therapy immediately (ex: chemotherapy, radiotherapy) (n = 3), old age (n = 2), existence of de novo T790M (n = 2), complications (n = 1) and physician’s choice (n = 1). Conclusions: Some patients who did not recieve re-biopsy had some target lesions and it could be increase the re-biopsy rate.

Correlation of low CT attenuation and necrotic features of tumor in contrast-enhanced CT with nivolumab response

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Background: Anti-PD1/PD-L1 antibodies, including nivolumab, produce durable responses in non-small cell lung cancer (NSCLC), but the response rate is about 20% in unselected NSCLC. Identifying predictive markers of response is necessary. Although PD-L1 expression may be a potential biomarker, evaluating whole tumors based on a small sample is difficult. Identifying radiographic features of responders can be very useful. We hypothesized that low attenuation on computed tomography (CT), considered to represent necrosis, correlates with nivolumab response. Methods: We retrospectively evaluated contrast-enhanced CT images before treatment and tumor response in 60 patients receiving nivolumab. The largest tumor lesion was characterized in each patient. CT attenuation (CTA) of whole tumor areas was measured; the presence of radiological findings of necrosis (necrotic features), presenting cavitation or ring- or patchy-enhancement in tumors, were assessed. We evaluated the association between CT imaging characteristics and nivolumab response and that between CT imaging characteristics and PD-L1 expression in tumors. Results: Thirty-nine target lesions in lung, 12 in lymph node, and 9 in other organs were chosen. The mean CTA was 58.5 ± 15.3 HU. Necrotic feature were observed in 24 (40%) of 60 lesions.Twenty of 60 lesions (33%) shrank to > 30% with nivolumab treatment. Mean CTA in responding lesions was 48.6 HU, significantly lower than that in nonresponding lesions (63.4 HU) (p < 0.001). The response rate of lesions with/without necrotic features was 45% and 28%, respectively (p = 0.246).Systemic tumor response, assessed by RECIST v1.1, was confirmed in 20 (33%) patients. Mean CTA of target lesions was lower in responders than patients with stable disease or progressive disease (51.4 vs. 62.0 HU, p = 0.011). The systemic response rate of lesions with/without necrotic features was 50% and 25%, respectively (p = 0.081).Mean CTA of target lesions was lower in tumors with high PD-L1 expression than in tumors with low PD-L1 expression (54.8 vs. 64.4 HU, p = 0.045). Conclusions: Low CTA and necrotic features in CT may correlate with nivolumab response. Tumors with low CTA may have high PD-L1 expression.

Abstract P6-07-34: The prognostic impact of inositol polyphosphate 5-phosphatase PIPP (INPP5J) expression in breast cancer tissue

Background : Inositol polyphosphate 5-phosphatase PIPP (INPP5J) has been identified as a suppressor of oncogenic PI3K/Akt signaling in breast cancer.INPP5J depletion increases transformation and accelerates oncogene-driven tumor growth in vivo, while paradoxically reducing cell migration, invasion, and metastasis. Therefore, we hypothesized that INPP5J gene expression in human breast cancer tissues would be prognostic in early breast cancer patients over long-term follow-up.

Methods: A total of 478 breast cancer tissue samples collected between 2003 and 2008 was available for analysis. We measured INNPP5J mRNA using a TaqMan gene expression assay. PIK3CA mutation status was evaluated using a TaqMan mutation detection assay. We then investigated the correlations of clinicopathological factors and prognosis with levels of INPP5J mRNA and the PIK3CA mutation status.

Results: INPP5J mRNA was expressed at a low level in 30.1% (144/478) and at a medium to high level in the remaining breast cancer samples. Low INPP5J mRNA correlated with larger tumor (p=0.015), high grade (p&lt;0.0001) and, ER-negativity (p&lt;0.0001). PIK3CA mutations were detected in 46% (63/138) of patients analyzed. We found that disease-free survival (DFS) was significantly worse in patients with low levels of INPP5J (p=0.008). Although DFS and INPP5J levels tended to be associated in estrogen receptor (ER)-positive patients (p=0.052), DFS was significantly worse in patients with wild-type PIK3CA and low INPP5J mRNA expression (p=0.008).

Conclusion: We shows that the level of INPP5J mRNA expression is prognostics in breast cancer patients and that its prognostic impact is affected by PIK3CA mutation status.

Citation Format: Kondo N, Kim T-S, Wanifuchi Y, Hato Y, Hisada T, Nishimoto M, Nishikawa S, Toyama T. The prognostic impact of inositol polyphosphate 5-phosphatase PIPP (INPP5J) expression in breast cancer tissue [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-07-34.

Abstract P2-03-07: Exome sequencing of human breast cancer tissues resistant to taxanes

Background: Although taxanes are a mainstay of breast cancer treatment, some cases are resistant to these drugs. This is a crucial issue in breast cancer therapy. In the emerging era of next-generation sequencing, it is possible to obtain extensive genomic information on individual tumors in a very short time. Using this technology, it was reported that specific mutations might affect therapeutic efficacy and induce resistance to specific treatment.

Objective: The aim of this study was to investigate the mechanisms of taxane resistance using whole exon sequencing and expression analyses in human breast cancer tissues.

Materials and Methods: We selected six breast cancer patients whose tumors responded well to anthracycline treatment but suffered disease progression on taxane treatment. We then performed whole exon sequencing on these samples using HiSeq (Illumia). In this way, we identified somatic mutations of candidate genes considered to be instrumental for mediating resistance to taxanes. Next, we performed mRNA expression analyses of these candidate genes in a further 122 breast cancers treated with taxanes at our institute. Finally, we correlated mRNA expression levels of these genes with clinicopathological factors and prognosis.

Results: We identified 9 mutations common to all 6 patients analyzed in this study, and a further 16 mutations shared by 5 of them. Kaplan-Meier analyses showed that high level mRNA expression of 3 of these 25 genes was significantly associated with poorer disease-free survival. Moreover, high level mRNA expression of one of these three genes was significantly associated with worse overall survival. However, there were no significant correlations between expression levels of these three genes and any clinicopathologeical features.

Conclusion: Using next-generation sequencing, we have identified three candidate genes involved in resistance to taxane treatment in breast cancer. We are now analyzing the functional attributes of these three genes.

Citation Format: Endo Y, Dong Y, Kondo N, Hato Y, Hisada T, Nishimoto M, Nishikawa S, Takahashi S, Toyama T. Exome sequencing of human breast cancer tissues resistant to taxanes [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-03-07.